[PATCH libXi v2] SizeClassInfo can return 0 even without an error

[Peter Hutterer]

On Sat, Oct 15, 2016 at 01:48:19PM +0200, Niels Ole Salscheider wrote:
> With this patch we catch the error case separately. Previously, it
> was not possible to distinguish between a size of 0 and an error.
> XListInputDevices assumed that a return value of 0 indicates an
> error and returned an error itself.
> 
> This caused a crash in any application that uses Chromium since it
> does not handle the error case properly.
> 
> v2: Do not set size in case of an error.
> 
> Signed-off-by: Niels Ole Salscheider <niels_ole at salscheider-online.de>
> ---

did you see https://patchwork.freedesktop.org/patch/115413/? I'd rather take
that one given that it already has a rev-by, I tested it and it's more
precise in the commit message.

Cheers,
   Peter

>  src/XListDev.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/src/XListDev.c b/src/XListDev.c
> index f850cd0..b2bad72 100644
> --- a/src/XListDev.c
> +++ b/src/XListDev.c
> @@ -73,10 +73,10 @@ static int pad_to_xid(int base_size)
>      return ((base_size + padsize - 1)/padsize) * padsize;
>  }
>  
> -static size_t
> -SizeClassInfo(xAnyClassPtr *any, size_t len, int num_classes)
> +static int
> +SizeClassInfo(xAnyClassPtr *any, size_t len, int num_classes, size_t *size_out)
>  {
> -    int size = 0;
> +    size_t size = 0;
>      int j;
>      for (j = 0; j < num_classes; j++) {
>          switch ((*any)->class) {
> @@ -91,7 +91,7 @@ SizeClassInfo(xAnyClassPtr *any, size_t len, int num_classes)
>                      xValuatorInfoPtr v;
>  
>                      if (len < sizeof(v))
> -                        return 0;
> +                        return 1;
>                      v = (xValuatorInfoPtr) *any;
>                      size += pad_to_xid(sizeof(XValuatorInfo) +
>                          (v->num_axes * sizeof(XAxisInfo)));
> @@ -101,11 +101,11 @@ SizeClassInfo(xAnyClassPtr *any, size_t len, int num_classes)
>                  break;
>          }
>          if ((*any)->length > len)
> -            return 0;
> +            return 1;
>          *any = (xAnyClassPtr) ((char *)(*any) + (*any)->length);
>      }
> -
> -    return size;
> +    *size_out = size;
> +    return 0;
>  }
>  
>  static void
> @@ -220,8 +220,7 @@ XListInputDevices(
>  	sav_any = any;
>  	end = (char *)list + rlen;
>  	for (i = 0; i < *ndevices; i++, list++) {
> -            s = SizeClassInfo(&any, end - (char *)any, (int)list->num_classes);
> -            if (!s)
> +            if(SizeClassInfo(&any, end - (char *)any, (int)list->num_classes, &s))
>                  goto out;
>              size += s;
>  	}
> -- 
> 2.10.1
>